Device comprising a gas-and/or vapor-filled discharge tube



April 8, 1950 P. SCHOUWSTRA ETAL DEVICE COMPRISING A GAS-AND/ORVAPOR-FILLED DISCHARGE TUBE Filed April 27, 1946 INVENTORS;

PIETER SCHQUWSTRA, PETRUS JOHANNES MARIA MUTSAERS,

BY UJMUJ 0 KW THEIR ATTORNEY i atented Apr. 18, 1956 UN STATES oFFiicsSection '1, Public Law 690, August 8, 1946 Patent expires November 16,1962 (01. sis-51) '2 claims. 1

This invention concernsa device comprising a gasand/or vapor-filleddischarge tube, an iriductance mainly for ignition purposes and anautomatic, for instance thermal, circuit breaking switch which isconnected in parallel with the tube. On opening the switch theinductance in the device referred to delivers a voltage impulseinitiating the ignition er the tube. Such an inductance is mainlyrequired when the stabilisation impedance is not possessed of anyappreciable inductance such as is the case with condensers and ohmicresistances, and for instance incandescent lamps. The inductance mayalso be required when the stabilisation impedance of the tube possessesan inductance, but which is zero or low before ignition. This occurs incircuit arrangements in which the value of the inductance isartificially reduced by counter windings, magnetic or other expedientsbefore ignition, in order that the electrodes of the tube may be heatedmore rapidly.

The location or mountingof the additional inductance for igniting thedischarge tube, which is usually connected in series with the tube, butmay also be connected in parallel with the tube in many cases, entailsdifficulties.

The present invention purports to avoid this mounting difficulty. Thenovelty is based on the realisation that the value of the inductance maybe comparatively low, in many cases of the order of magnitude of mI-I.

According to our invention the circuit breaking switch is equipped witha cylindrical envelope on which are wound the turns of the inductance.Between the switch and the winding of the inductance coil 2. tube may beprovided which is slotted in an axial direction and made from a materialwhich is a better magnetic conductor than air. This measure permits ofreducing the number of turns of the inductance coil. The said slottedtube may often constitute the envelope of the switch.

In the devices referred to in the preamble use is often made ofcondensers that are connected to the electrodes of the discharge tube.The impedance of such condensers, which are usually employed inalternating current installations and which mainly serve for the removalof radio interferences, is a multiple of the tube impedance. In anadvantageous form of construction of our invention the plates of thiscondenser surround the axis of the switch envelope helicoidally. In thiscase the plates are provided on the inductance coil or below the latter.

The units including the interruptor, inductance device are so housed asto be invisible. This method is particularly suitable for elongated discharge tubes having two holders, for instance, for luminescent mercuryvapor tubes having a low vapor pressure.

As an alternative the unit may be incorporated in a cap of the dischargetube. This mounting method is particularly suitable for discharge tubeshaving only one cap, for instance u-shaped sodium vapor discharge tubes.

The novelty will be more fully explained by reference to theaccompanying drawing, given by way of example.

Figure 1 of this drawing represents a wiring diagram of a deviceconstituting the object of the present novelty. Between the terminals land 2 of the device are connected in series with each other anincandescent lamp 3, the heater winding 4 of a thermal switch, aninductance coil 5, an electrode 6 for a discharge tube 1, a bimetallicelement 8 cooperating with the heater winding 4, a contact member 9provided thereon, a counter contact member Ill cooperating therewith andthe second electrode I l of the discharge tube 1. When connecting theterminals I and 2 of the device to a suitable supply e. g. A. C. mainsof 220 volts-50 cycles/sec. the incandescent lamp 3 is made to glow andthe filamentary electrodes 5 and l l of the discharge tube equipped withelectron emitting material, are heated. At the same time heat issupplied from the heater winding 4 to the bimetallic element 8. Thisbimetallic element is so shaped as to warp as a result thereof in suchmanner that the contact members 9 and ill move away from one another.Owing to this interruption between the members 9 and It the currentthrough the inductance coil 5 is also interrupted, whereupon itsmagnetic field breaks down and yields a voltage impulse capable ofinitiating the discharge between the electrodes 6 and II of thedischarge tube 1 now having the emission temperature.

In Fig. 2 the discharge tube '1 of this device is representedseparately. This discharge tube may, for instance, be a sodium vaporlamp designed for the emission of light.

The thermal switch shown in Fig. 1, which consists of the heatingelement 4, the bimetallic element 8 furnished with the contact member 9,and the counter contact member ill is incorporated in a tubular orcylindrical exhausted envelope l2. For ease of reading solely theenvelope l2 of the switch is represented in Fi 2. This envelope I2carries a frictionally engaging cylinder 13 which is slotted in an axialdirection and consists of, for example, a strong magnetically permeablemetal sheet having a thickness of 0.4 mm. This cylinder carries theinductance coil which consists of about 150 turns of strong copper wirehaving a thickness of 0.5 mm. The said slit of the tube l3 has a widthof about 1 mm. This unit, which includes the switch l2 and theinductance coil 5, is supported by the connecting wires to the electrodeof the discharge tube and to the terminals of the base assembly orGoliath cap 14 surrounding them. Between the unit and the cap may beprovided a filling mass, if required. An anti-interference condenser ofabout 10.000/L/Lf, which may be available and is indicated in dottedlines at 15 in Fig. 1, may be provided as a wound condenser on thecylindrical surface of the inductance coil 5.

What we claim is:

1. In combination, an arc discharge device of the type employing anionizable medium and comprising a plurality of electrodes at least oneof which is of the filamentary type, an enclosing envelope surroundingsaid are discharge device, a generally cylindrical base assembly securedto said enclosing envelope, a starting switch enclosed within acylindrical envelope and mounted within said base assembly axiallythereof and having its contacts electrically connected in parallel withsaid arc discharge device, a metallic cylinder surrounding saidcylindrical envelope,

and a ballasting inductance in series with said are discharge device andwound around said metallic cylinder.

2. In combination, an arc discharge device ofthe type employing anionizable medium and comprising a plurality of electrodes at least oneof which is of the filamentary type, an enclosing envelope surroundingsaid are discharge device, a generally cylindrical base assembly securedto said enclosing envelope, a starting switch enclosed within acylindrical envelope and mounted within said base assembly axiallythereof and having its contacts electrically connected in parallel withsaid arc discharge device, a magnetically permeable cylinder surroundingand frictionally engaging said cylindrical envelope, a ballastinginductance in series with said are discharge device and wound aroundsaid metallic cylinder, and a condenser comprising a pair of cylindricalplates surrounding said cylindrical envelope.

PIETER SCHOUWSTRA.

PETRUS J OHANNES MARIA MUTSAERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,297,885 Gustin et a1. Oct. 6,1942 2,313,745 Hays et al Mar. 16, 1943 FOREIGN PATENTS Number CountryDate 310,895 Great Britain Oct. 2, 1930

